1. Field of the Invention
The field of the invention is a system for preventing overheating, of an engine for a vehicle, comprising a detector for measuring the engine rotation speed and a power output reducing means for reducing an engine power output in response to a value detected in the revolution rate detector exceeding a preset revolution rate.
2. Description of the Prior Art
Systems of this type are conventionally known, for example, from Japanese Patent Application Laid-open No. 66839/86. In such a prior art system, to prevent overheating when the engine is unnecessarily racing, such as when the vehicle is stopped, a preset engine speed (revolution rate) which controls fuel cut-off is gradually reduced in response to lowering in the actual engine speed, so as to reduce power output.
The above system is intended to be operated when the vehicle is stopped. However, the engine tends to overheat during travelling of the vehicle and hence, a system for preventing such overheating is desired. Moreover, during vehicle travel the engine can be cooled by air flowing into an engine room, and it is preferable that the engine overheating is prevented with use of a cooling effect provided by the flowing or travelling air.